Borrowed ♭VII (Mixolydian) Check

Check explicitly spelled lowered-seventh major triad relative to major tonic (Mixolydian collection marker), not enharmonic A# or proof of borrowed harmonic intent.

Description

A borrowed flat-seven major chord is spelled on the lowered seventh of a major tonic.

A borrowed flat-seven major chord is spelled on the lowered seventh of a major tonic. Enharmonic equality alone loses that degree evidence.^[1]

Enter pitch-class major tonic, observed root and supported quality. Return match, spelled degree and signed alteration.

When to use Borrowed ♭VII (Mixolydian) Check

Use Borrowed ♭VII (Mixolydian) Check when you need to evaluate the supplied records under the calculation and evidence rules below. This marks a collection relationship; it does not prove modal borrowing, intention or resolution.

Enter the written notes, explicit grouping, pitch observations or supported chord tokens requested. Keep scientific octaves, accidentals and caller evidence consistent.

How to use Borrowed ♭VII (Mixolydian) Check and understand its results

Enter the written notes, explicit grouping, pitch observations or supported chord tokens requested. Keep scientific octaves, accidentals and caller evidence consistent.
Enter majorTonic, observedChordRoot, observedChordQuality using the field table and calculation rules, then run the tool.
Read matchesBorrowedFlatSevenMajor, observedSpelledRootDegree, observedRootAlteration. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
majorTonic	Major tonic	string	Required
observedChordRoot	Observed chord root	string	Required
observedChordQuality	Observed chord quality	string	Required

Enter pitch-class major tonic, observed root and supported quality. Return match, spelled degree and signed alteration.

match=spelled degree7 AND alteration−1 AND major quality

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
matchesBorrowedFlatSevenMajor	Matches borrowed flat seven major	boolean
observedSpelledRootDegree	Observed spelled root degree	number
observedRootAlteration	Observed root alteration	number

json

{
  "input": {
    "majorTonic": "C",
    "observedChordRoot": "Bb",
    "observedChordQuality": "major"
  },
  "output": {
    "matchesBorrowedFlatSevenMajor": true,
    "observedSpelledRootDegree": 7,
    "observedRootAlteration": -1
  }
}

Limitations and assumptions

This marks a collection relationship; it does not prove modal borrowing, intention or resolution.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Neapolitan ♭II Chord Identifier: A Neapolitan triad uses the spelled lowered second as a major root. Its common first inversion is separate evidence from chord identity. For a complementary task, use Roman Numeral Chord Analysis: Roman analysis preserves a chord root’s written degree and chromatic alteration. Enharmonic sounding equality can conceal different written functions.

References

Borrowed ♭VII (Mixolydian) Check — tool.io

Similar or alternative tools

Neapolitan ♭II Chord Identifier
A Neapolitan triad uses the spelled lowered second as a major root. Its common first inversion is separate evidence from chord identity.
Roman Numeral Chord Analysis
Roman analysis preserves a chord root’s written degree and chromatic alteration. Enharmonic sounding equality can conceal different written functions.